High-dose methadone and the need for drug measurements in plasma.

We report a case of high-dose methadone prescribed to a heroin addict for pain control. The patient was prescribed methadone during convalescence from surgery and subsequently for maintenance treatment. Dosing was started at 360 mg of methadone per day and reduced over 12 days to an 80 mg/day maintenance dose. Although the patient was drowsy on the initial dose, his recovery was uneventful. However, there were complaints of pain and withdrawal discomfort when the plasma concentration decreased to less than 1 mg/L. Measurements of methadone in plasma were helpful for monitoring the recovery of this patient after surgery and are likely to prove useful in similar cases.